Fig. 4. Nuclear pMAPK following Spitz activation in S2 cells. S2 cells were stained for Egfr antigen, pMAPK antigen and DNA as indicated. Conditions are as in Fig. 2A and Fig. 3, see text. Transfected DNA and temperature are indicated on the left. Transfected cells express elevated Egfr antigen (arrowheads), untransfected control cells do not. Note that cells transfected with Egfr^tsla, at 30°C, do not express pMAPK over background levels. Arrows indicate increased levels of pMAPK antigen. Scale bar: 5 µm.